As disclosed in Patent Document 1, for example, there is conventionally known a thermometer for measuring and accumulating a basal body temperature of a female and estimating a menstruation cycle from the accumulated basal body temperatures. Further, in recent years, there is known a system for transmitting measurement data measured by a thermometer from the thermometer to a server via a portable terminal such as a smart phone and thereby causing the server to display an expected next ovulation date or an expected menstruation start date on the portable terminal. In this system, the thermometer has a function of recording of a plurality of items of measurement data for 40 days, for example, and the thermometer can collectively transfer the measurement data to the server via the portable terminal on a holiday, for example. When transferring measurement data to the server, a user activates an application program of the portable terminal and logs in to the system, then selects data transfer on a display screen of the portable terminal, and places the thermometer and the portable terminal in the vicinity thereby to transfer basal body temperature data.